Optimized design of a stacked diaphragm MEMS pressure sensor for Tsunami warning system

Tsunami is a large scale, short duration vertical displacement of water column. Tsunami results in a pressure change in the sea bed. The Tsunami warning system (TWS) consist of a series of sensors which detect the change in pressure at the sea bed when tsunami waves are generated. Micro electro mechanical system based silicon pressure sensors have undergone a significant growth in the last few years. The sensitivity, maximum measurable pressure and linear range over the deflection of pressure sensor highly depend upon the diaphragm structure. In this work, a stacked diaphragm pressure sensor is designed and simulated which can be used for under water pressure measurements. A novel method for sensitivity enhancement by optimizing the thickness of various layers for stacked diaphragms is presented. Also a study of the bulk micro machined silicon piezoresistive pressure sensor and a surface micro machined stacked diaphragm pressure sensor is presented, simulated and compared with respect of sensitivity and deflection.